In recent years, concern about development of environmentally friendly alternative energy sources and diversification of future energy sources has become an international issue due to fossil fuel depletion, and solar batteries based on solar energy have attracted attention as alternative energy sources.
Generally, photovoltaic power generation uses characteristics of semiconductors to convert light energy into electrical energy, in which direct current (DC) generated by a solar battery is converted into alternating current (AC) in order to supply domestic electrical power. However, the photovoltaic power generation has such weak electromotive force that plural units, i.e. unit solar-battery modules, are connected to each other on a plate to produce a suitable electromotive force and may mostly be integrated, particularly, into constructions, such as buildings, houses or the like.
The minimum unit of a solar battery is called a cell, but the solar cell is rarely used as a unit cell in practice. Since a single cell generates a voltage of about 0.5 V, which is much lower than the several to hundreds of volts required in practical use, plural unit solar batteries are connected in series or in parallel according to desired unit capacity. To protect the plural cells connected according to desired unit capacity, the plural cells are packaged to constitute a solar cell panel. Electricity produced by the solar cell panel is supplied to buildings or the like.
In the related art, a solar cell panel is simply attached to a roof or outer wall of a construction, causing deterioration in an outer appearance of the construction. Further, since the conventional solar cell panel can be attached only to a roof or an outer wall, there is a limit in application ranges of solar cells. Further, the solar cell panel is configured to absorb sunlight to produce electricity, and it is thus advantageous to arrange the solar cell panel as perpendicular to sunlight as possible. However, it is difficult to mount the conventional solar cell panel to be varied perpendicularly to sunlight.